Synthesis of Water-Dispersible Maghemite Nanocrystals using 6-Aminohexanoic Acid as a Capping Agent

This paper describes a simple route to synthesis of water-dispersible monodisperse maghemite (γ-Fe₂O₃) nanocrystals using 6-aminohexanoic acid (AHA) as a stabilizer. The water-dispersible γ-Fe₂O₃ nanocrystals with an average size of 5 nm were obtained simply by addition of Fe(CO)₅ into an octyl ether solution containing AHA at 195 .deg. C under argon condition. As-prepared AHA coated γ-Fe₂O₃ nanocrystals exhibited highly crystallinity and magnetic property while keeping a good dispersity in an aqueous phase. We also obtained water-dispersible AHA coated γ-Fe₂O₃ nanocrystals using ligand-exchange method, demonstrating that AHA can be a good candidate for preparing water-dispersible uniform metal oxide nanocrystals